Coating liquid for preparing pcbm electron transport layer and application thereof

Abstract

The application discloses a coating liquid for preparing a PCBM electron transport layer and application thereof. The coating liquid comprises a PCBM precursor, a lithium salt, an organic polymer and a methylamine halide salt. The coating liquid provided by the application improves the conductivity of the PCBM electron transport layer, increases the electron mobility, reduces the series resistance, increases the carrier recombination resistance, reduces the carrier recombination, improves the electron transmission and extraction efficiency, and further improves the open-circuit voltage, the short-circuit current and the fill factor of the prepared perovskite solar cell, finally improves the efficiency of the perovskite solar cell and the assembly; and the application method provided by the application is simple in process, low in cost and beneficial to commercial application.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of perovskite devices, and particularly relates to a coating liquid for preparing a PCBM electron transport layer and application thereof. BACKGROUND

[0002] At present, the photoelectric conversion efficiency of perovskite solar cells with small area size has reached 25.7% in the laboratory, which is not much different from the efficiency (26.5%) of single-crystal silicon cells with small area size in the laboratory. More and more enterprises are committed to promoting the industrial production of perovskite solar cells and commercializing the application of perovskite solar modules as soon as possible. Almost all perovskite solar cell enterprises adopt the inverted structure perovskite solar cell as the mainstream technology because the hysteresis effect of the inverted structure perovskite solar cell is not obvious, the stability of the cell and module is good, and the industrial production of the inverted structure perovskite solar cell is more operable and has lower process difficulty than the normal structure perovskite solar cell.

[0003] In the inverted structure, there are two types of commonly used electron transport layer (ETL) materials. One type is inorganic metal oxide mainly including TiO2 and SnO2. Because of the relatively good performance, inorganic metal oxide mainly including TiO2 and SnO2 is favored by researchers as the electron transport layer in the normal structure perovskite solar cell, and most normal structure perovskite solar cells select inorganic metal oxide mainly including TiO2 and SnO2 as the electron transport layer material. However, when applied in the inverted structure, the process preparation and performance of inorganic metal oxide mainly including TiO2 and SnO2 have certain limitations. For example, if inorganic metal oxide mainly including TiO2 and SnO2 is used to prepare the electron transport layer by the solution method, the particle size of TiO2 and SnO2 cannot be too large due to the limitation of the selection of the solvent, and the good conductivity of TiO2 and SnO2 cannot be lost, so that the material preparation method is limited, and the two are mutually restricted, ultimately resulting in that the synthesis process and film forming process of inorganic metal oxide mainly including TiO2 and SnO2 for preparing the electron transport layer by the solution method are difficult, and the performance of the prepared electron transport layer is greatly discounted. In addition, if inorganic metal oxide mainly including TiO2 and SnO2 is used to prepare the electron transport layer by the vacuum deposition method, the perovskite photoactive layer will be damaged to a certain extent in the deposition process, and thus a protective layer needs to be prepared on the perovskite photoactive layer, so that the process of the perovskite solar cell and module is increased. In addition, due to the high requirements of the protective layer on the film thickness and electrical properties, it is necessary to ensure that the electrical properties of the whole cell are not affected while the perovskite photoactive layer is well protected from damage, and the solvent that can be selected must be a solvent with small polarity that does not damage the perovskite, so that the selectivity of the protective layer is limited, and thus the preparation process of the perovskite solar cell is difficult and complicated, and the preparation cost is high, which is not conducive to the industrial development of the perovskite solar cell.

[0004] Different from the above inorganic metal oxide, another kind of electron transport layer material is the organic small molecule electron transport layer material of C60, PCBM and its derivative fullerene. Since the performance of C60 is low, it is rarely used at present, and other fullerenes and their derivatives are difficult to synthesize and purify, and the cost is high, so they are also rarely used. As a representative of such electron transport layer material, PCBM is currently used as an electron transport layer material in most inverted structures due to its relatively good performance.

[0005] Now the synthesis and purification process of PCBM is very mature and large-scale, which makes the price of PCBM lower and lower. At the same time, when PCBM is used to prepare the electron transport layer, coating, scraping and spraying and other relatively simple and low-difficulty operation and low-cost equipment processes can be selected, so that the preparation process of the electron transport layer is simple, the cost is low and the repeatability is strong, which is suitable for industrial application, so as to promote the industrialization development of perovskite. However, the electrical performance of pure PCBM is generally limited, and the solvents such as chlorobenzene and chloroform used to dissolve PCBM are toxic solvents, which are not conducive to the health of the operators and the environment, and are not conducive to the use of PCBM as an electron transport layer material in the industrialization development of perovskite. At the same time, the stability of perovskite solar cell is also a difficult problem to further industrialize perovskite solar cell, which needs to be solved urgently.

[0006] In summary, the prior art has the following problems:

[0007] 1. In the prior art, inorganic metal oxides such as TiO2 and SnO2 are not suitable for inverted structure.

[0008] 2. In the prior art, the electrical performance of PCBM is generally limited, which limits the photovoltaic performance of the prepared perovskite solar cell. SUMMARY

[0009] In view of the deficiencies of the prior art, the purpose of the present application is to provide a coating liquid for preparing a PCBM electron transport layer and its application.

[0010] To achieve the above-mentioned purpose of the application, the technical scheme adopted by the present application comprises:

[0011] In a first aspect, the present application provides a coating liquid for preparing a PCBM electron transport layer, which comprises a PCBM precursor, and further comprises a lithium salt, an organic polymer and a methylamine halide salt.

[0012] In a second aspect, the present application further provides a preparation method of a PCBM electron transport layer, comprising:

[0013] providing the above-mentioned coating liquid;

[0014] coating the coating liquid to form a liquid film;

[0015] performing heat treatment on the liquid film to obtain a PCBM electron transport layer.

[0016] In a third aspect, the present application also provides a perovskite device, comprising a hole transport layer, a perovskite photoactive layer, and an electron transport layer, wherein the electron transport layer is prepared by the above preparation method.

[0017] In a fourth aspect, the present application also provides a method for preparing a perovskite device, comprising:

[0018] forming a hole transport layer on the surface of the conductive substrate;

[0019] forming a perovskite photoactive layer on the surface of the hole transport layer;

[0020] forming an electron transport layer on the surface of the perovskite photoactive layer by the above preparation method; and

[0021] forming an electrode layer on the surface of the electron transport layer.

[0022] Based on the above technical solutions, compared with the prior art, the present application has at least the following beneficial effects:

[0023] The coating liquid and its application provided by the present application are doped with a certain proportion of lithium salt and organic polymer material. After doping lithium salt, the conductivity of PCBM is significantly improved, the electron mobility is improved, after doping organic polymer material, the film forming quality of PCBM is improved, the surface roughness of the PCBM film is reduced, and the carrier recombination center is reduced, so that the conductivity of the electron transport layer prepared by doping lithium salt and organic polymer material in PCBM is improved, the electron mobility is improved, the series resistance is reduced, the carrier recombination resistance is increased, and the carrier recombination is reduced, thereby improving the transmission and extraction efficiency of electrons, and further improving the open-circuit voltage (Voc), short-circuit current (Jsc), and fill factor (FF) of the prepared perovskite solar cell, and finally improving the efficiency of the perovskite solar cell and module. In addition, the technical solution provided by the present application is also doped with a certain proportion of methylamine halide salt, so as to make up for the B-site cation defects, such as Pb vacancy defects, generated by the escape of methylamine ions during the annealing process of the perovskite photoactive layer, maintain the stoichiometric ratio of the perovskite photoactive layer, and stabilize the perovskite photoactive layer, thereby improving the stability of the perovskite solar cell and module.

[0024] The application method of the coating liquid provided by the present application has a simple process and low cost, and at the same time, the preparation process of the high-efficiency perovskite solar cell and module is simple, the process time is short, the cost is low, it is environmentally friendly and healthy, the stability is good, it is suitable for industrialization of perovskite solar cells, and it is conducive to promoting commercialization of perovskite solar modules.

[0025] The above description is only a summary of the technical solutions of the present application. In order for those skilled in the art to more clearly understand the technical means of the present application and can be implemented in accordance with the content of the description, the following is the preferred embodiment of the present application and the detailed description of the drawings as follows. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 is a structure schematic diagram of a perovskite device provided by an embodiment of the present application.

[0027] BRIEF DESCRIPTION OF DRAWINGS

[0028] 111, perovskite light-sensitive layer; 112, hole transport layer; 113, electron transport layer. DETAILED DESCRIPTION

[0029] In view of the deficiencies in the prior art, it is necessary to address the problems in the prior art that the inverting structure perovskite solar cell and assembly prepared by using TiO2, SnO2 as the main inorganic metal oxide as the electron transport layer material has high process difficulty, high equipment cost, low photovoltaic performance, and is not conducive to the industrialization development of perovskite solar cells; and the use of PCBM as the electron transport layer, due to the general electrical performance of PCBM, the photovoltaic performance of the prepared perovskite solar cell is limited, and the solvents such as chlorobenzene and chloroform used to dissolve PCBM are toxic solvents, which are not conducive to the health of the operators and environmental protection, and are not conducive to the use of PCBM as the electron transport layer material in the industrialization development of perovskite; at the same time, the stability of the perovskite solar cell needs to be improved, etc. The present inventors have long-term research and a large number of practices, and provide a high-performance and green solvent-dissolved doped PCBM as an electron transport layer material to prepare a high-efficiency and stable perovskite solar cell and assembly.

[0030] In the following description, many specific details are set forth in order to provide a thorough understanding of the present application, however, the present application can be practiced in other ways different from those described herein, therefore, the scope of protection of the present application is not limited by the specific embodiments disclosed below.

[0031] The present application provides a coating liquid for preparing a PCBM electron transport layer, which comprises a PCBM precursor, a lithium salt, an organic polymer and a methylamine halide salt.

[0032] The principle of the above-mentioned embodiments is to prepare a high-performance PCBM electron transport layer by doping lithium salt, methylamine halide salt and organic polymer in PCBM. After doping lithium salt, the conductivity of PCBM is significantly improved, and the electron mobility is improved. After doping organic polymer material, the film quality of PCBM is improved, the surface roughness of PCBM film is reduced, and the carrier recombination center is reduced. Therefore, after doping lithium salt and organic polymer material, the conductivity of the prepared electron transport layer is improved, the electron mobility is further improved than that of the lithium salt alone, the series resistance is reduced, the carrier recombination resistance is increased, the carrier recombination is reduced, and the electron transport and extraction efficiency is improved. By adding a certain proportion of methylamine halide salt, the Pb vacancy defects generated by the escape of methylamine ions in the perovskite photoactive layer during the annealing process are supplemented, and the stoichiometric ratio of the perovskite photoactive layer is maintained. The finally prepared PCBM electron transport layer film is more dense and uniform, and has better conductivity. The defects caused by the escape of methylamine ions in the perovskite photoactive layer during the annealing process are supplemented, and the stoichiometric ratio of the perovskite photoactive layer is stabilized, thereby improving the electrical properties of the PCBM electron transport layer and the stability of the perovskite photoactive layer, reducing the carrier recombination center, reducing the carrier transport resistance, increasing the carrier recombination resistance, and further improving the effective transport and extraction efficiency of the electron, reducing the series resistance of the corresponding device, and finally greatly improving the efficiency and stability of the perovskite device, such as perovskite solar cell and module.

[0033] In some embodiments, the lithium salt can include any one or a combination of two or more of lithium bis(trifluoromethyl) sulfonylimide, lithium bis(fluorosulfonyl) imide, and lithium trifluoromethanesulfonate.

[0034] In some embodiments, the mass of the lithium salt in the coating solution can be 2-10% of the mass of the PCBM precursor.

[0035] In some embodiments, the organic polymer can include any one or a combination of two or more of PMMA, PEI, and PEG.

[0036] In some embodiments, the mass of the organic polymer in the coating solution can be 2-10% of the mass of the PCBM precursor.

[0037] In some embodiments, the methylamine halide salt can include any one or a combination of two or more of MACl, MABr, and MAI.

[0038] In some embodiments, the mass of the methylamine halide salt in the coating solution can be 1-5% of the mass of the PCBM precursor.

[0039] In some embodiments, the solvent of the coating solution can include anisole. The technical solution has the beneficial effect that anisole, a commonly used food additive green solvent, is used to dissolve PCBM, thereby solving the health and environmental problems of using PCBM as an electron transport layer material for the operating personnel, and because anisole has stronger binding ability with C60 and benzene rings in PCBM, it prevents PCBM from aggregating during film formation, thereby enabling ordered accumulation of molecules and preparing a more uniform and dense PCBM electron transport layer film.

[0040] The solvent used in the high-performance PCBM electron transport layer provided by the embodiments of the present application is anisole, which is a healthy and environmentally friendly green solvent, thereby making the perovskite battery and component more environmentally friendly and safe during preparation, and thereby facilitating the industrialization and sustainable development of perovskite solar cells. In addition, the performance of PCBM as an electron transport layer is improved, thereby making the preparation process of high-efficiency perovskite solar cells and components simpler and requiring lower equipment, thereby making the industrialization cost of perovskite solar cells lower and the process simpler, and thereby promoting the commercial application of perovskite solar cells and components.

[0041] In some embodiments, the concentration of the PCBM precursor in the coating solution can be 15-30 mg / mL.

[0042] As some typical examples of the above technical solution, the lithium salt doped in the high-performance PCBM electron transport layer material is any one or a combination of two or more of lithium bis(trifluoromethyl) sulfonylimide, lithium bis(fluorosulfonyl) imide, and lithium trifluoromethanesulfonate, and the doping ratio is 2%-10% of the mass of PCBM. At this ratio, the phenyl ether can not only dissolve the lithium salt well, but also greatly improve the conductivity of PCBM after doping the lithium salt, which is conducive to improving the electron mobility of PCBM as an electron transport layer, improving the recombination resistance of carriers in the corresponding battery and component, reducing the transmission resistance of the battery and component, thereby facilitating the extraction and transmission of electrons, reducing the series resistance, and ultimately improving the photovoltaic performance of the perovskite battery and component.

[0043] The organic polymer material doped in the high-performance PCBM electron transport layer material is any one or a combination of two or more of PMMA, PEI, and PEG, and the doping ratio is 2%-10% of the mass of PCBM. At this ratio, the phenyl ether can dissolve the organic polymer material well, and the PCBM doped with the organic polymer material has better film formation quality, is uniform and dense, and has very low roughness, which is conducive to the deposition of the transparent conductive electrode on the electron transport layer, reduces the carrier recombination center, improves the efficiency of carrier collection, and thereby improves the photovoltaic parameters of the corresponding perovskite solar cell and component.

[0044] The doped methylamine halogen salt in the high-performance PCBM electron transport layer material is any one of MACI, MABr and MAI or a combination of two or more thereof, and the doping ratio is 1-5% of the mass of PCBM. Under this ratio, the anisole can well dissolve the methylamine halogen salt, and after doping the methylamine halogen salt, the perovskite defects caused by the escape of methylamine ions during the annealing heating process can be well supplemented, for example, it can well combine with exposed Pb, reduce Pb vacancy defects, maintain the stoichiometric ratio of the perovskite light-sensitive layer, thereby improving the stability of the perovskite light-sensitive layer, and further improving the stability of the perovskite solar cell and module.

[0045] The embodiment of the present application also provides a preparation method of a PCBM electron transport layer, comprising the following steps:

[0046] The coating liquid in any of the above embodiments is provided.

[0047] The coating liquid is coated to form a liquid film.

[0048] The liquid film is heat-treated to obtain a PCBM electron transport layer.

[0049] In some embodiments, the temperature of the heat treatment can be 80-120 min, and the time can be 5-15 min.

[0050] Referring to Figure 1 The embodiment of the present application also provides a perovskite device, comprising a hole transport layer 112, a perovskite light-sensitive layer 111 and an electron transport layer 113, wherein the electron transport layer 113 is prepared by the preparation method in any of the above embodiments.

[0051] In some embodiments, the perovskite device can further comprise a conductive substrate and an electrode layer 130, and the conductive substrate, the hole transport layer 112, the perovskite light-sensitive layer 111, the electron transport layer 113 and the electrode layer 130 are sequentially stacked along a certain direction.

[0052] In some embodiments, the conductive substrate can comprise a carrier glass 140 and a transparent conductive film 120 coated on the surface of the carrier glass 140.

[0053] In some embodiments, the thickness of the hole transport layer 112 can be 20-100 nm.

[0054] In some embodiments, the thickness of the perovskite light-sensitive layer 111 can be 400-700 nm.

[0055] In some embodiments, the thickness of the electron transport layer 113 can be 40-120 nm.

[0056] Exemplarily, continuing to refer to Figure 1 , the perovskite device is a perovskite solar cell 100, comprising a carrier glass 140, a transparent conductive film 120 arranged on the carrier glass 140 as a conductive substrate, the transparent conductive film 120 forming a top electrode layer 130, and a cell main structure 110 between the conductive substrate and the top electrode layer 130; the cell main structure 110 comprises a perovskite photosensitive layer 111, a hole transport layer 112 on one side of the perovskite photosensitive layer 111, and an electron transport layer 113 on the other side of the perovskite photosensitive layer 111; the perovskite solar cell 100, the electron transport layer 113 is a high-performance PCBM electron transport layer 113 material solution coated by using anisole green solvent to dissolve a certain proportion of lithium salt, organic high molecular material and methylamine halide salt PCBM. The high-performance PCBM electron transport layer 113 material is dissolved in anisole, a commonly used food additive, which is a green solvent, thereby solving the health and environmental protection problems of using PCBM as the electron transport layer 113 material for the operator, and the combination of anisole and C60 and benzene ring in PCBM is stronger, thereby preventing PCBM from gathering during film forming, and further making the molecules orderly stacked, and preparing a more uniform and dense PCBM electron transport layer 113 film; meanwhile, the high-performance PCBM of the application is doped with a certain proportion of lithium salt and organic high molecular material, the conductivity of PCBM is significantly improved after doping lithium salt, the electron mobility is improved, the film forming quality of PCBM is improved after doping organic high molecular material, the surface roughness of PCBM film is reduced, and the carrier recombination center is reduced, so that the electron transport layer 113 prepared by doping PCBM with lithium salt and organic high molecular material has improved conductivity, improved electron mobility, lower series resistance, increased carrier recombination resistance, reduced carrier recombination, thereby improving the transmission and extraction efficiency of electrons, and further improving the open-circuit voltage (Voc), short-circuit current (Jsc) and fill factor (FF) of the prepared perovskite solar cell 100, and finally improving the efficiency of the perovskite solar cell 100 and the assembly. In addition, the high-performance PCBM is also doped with a certain proportion of methylamine halide salt, thereby making up the Pb vacancy defects generated by the escape of methylamine ions during the annealing process of the perovskite photosensitive layer 111, maintaining the stoichiometric ratio of the perovskite photosensitive layer 111, and stabilizing the perovskite photosensitive layer 111, thereby improving the stability of the perovskite solar cell 100 and the assembly.

[0057] The main function of the carrier glass 140 is to serve as a carrier for the transparent conductive film 120 electrode. The carrier glass 140 can be any conductive glass substrate. Preferably, the thickness of the carrier glass 140 is 1.1mm-2.5mm. This can ensure sufficient mechanical load bearing capacity, and reduce the absorption of light by the carrier glass 140, so that more light enters the main body structure 110 of the cell, thereby increasing the light absorption and utilization rate of the cell.

[0058] The main function of the transparent conductive film 120 electrode and the top electrode layer 130 is to conduct the photo-generated current. Specifically, the transparent conductive film 120 electrode is an FTO electrode, i.e. a fluorine-doped tin oxide electrode. This can enhance the absorption of ultraviolet light by the transparent conductive film 120 electrode, further reducing the entry of ultraviolet light into the electron transport layer 113; in addition, the FTO electrode also has the advantages of low resistivity and stable chemical properties. Of course, it can be understood that the transparent conductive film 120 electrode is not limited to the FTO electrode, but can also be an indium tin oxide (ITO) electrode, an indium titanium oxide (ITiO) electrode, an indium cerium oxide (ICO) electrode, an indium tungsten oxide (IWO) electrode, an aluminum-doped zinc oxide (AZO) electrode, or a boron-doped zinc oxide (BZO) electrode, etc.

[0059] Specifically, the top electrode layer 130 can also be a layer of material similar to the transparent conductive film 120, such as an indium tungsten oxide (IWO) electrode. Of course, it can be understood that the top electrode layer 130 is not limited to the indium tungsten oxide (IWO) electrode, but can also be other transparent conductive film 120 electrodes, such as fluorine-doped tin oxide (FTO), indium tin oxide (ITO), indium titanium oxide (ITiO) electrode, indium cerium oxide (ICO) electrode, indium tungsten oxide (IWO) electrode, aluminum-doped zinc oxide (AZO) electrode, or boron-doped zinc oxide (BZO) electrode.

[0060] In addition, it is obvious that since the electrode layer 130 does not need to be transparent, as long as the conductive requirement is met, a pure metal or alloy material coating can be used as the electrode layer 130, and relevant technical means are already known in the prior art, which need not be repeated here. Those skilled in the art can make appropriate choices according to the process requirements. Obviously, the focus of the present application is on the composition and preparation method of the above-mentioned electron transport layer 113, and the specific exemplary content of other layers in the embodiments only serves to facilitate those skilled in the art to fully refer to and understand the present application, and is not a limitation on the protection scope of the present application.

[0061] The main role of the hole transport layer 112 is to transport holes, and can also block electrons. Preferably, the thickness of the hole transport layer 112 can be 20-100 nm, so as to ensure film quality and reduce defects of the hole transport layer 112, and to ensure low internal series resistance, which is conducive to short-circuit current improvement. In the embodiment, the hole transport layer 112 is nickel oxide (NiO x ), which can be directly vacuum deposited on the transparent conductive film 120 electrode (FTO).

[0062] The main role of the high-performance PCBM electron transport layer 113 is to transport electrons, and can also block holes, thereby reducing hole-electron recombination, and playing a role of selective electron transport. In the embodiment, the thickness of the high-performance PCBM electron transport layer 113 is preferably 40-120 nm. At this thickness, the high-performance PCBM electron transport layer 113 has good film quality, low internal series resistance of the battery, and can effectively extract and transport electrons, block holes, reduce hole-electron recombination, and is conducive to improving the short-circuit current and fill factor of the perovskite solar cell and module.

[0063] The embodiment of the present application also provides a perovskite solar module, which can include the perovskite solar cell 100 provided in the above embodiment.

[0064] The embodiment of the present application also provides a perovskite device manufacturing method, which includes the following steps:

[0065] The step of forming a hole transport layer 112 on the surface of the conductive substrate.

[0066] The step of forming a perovskite photoactive layer 111 on the surface of the hole transport layer 112.

[0067] The step of forming an electron transport layer 113 on the surface of the perovskite photoactive layer 111 by using the preparation method in any of the above embodiments; and

[0068] The step of forming an electrode layer 130 on the surface of the electron transport layer 113.

[0069] The application provides a high-performance PCBM electron transport layer 113 material which has good electrical performance, is dissolved by a green solvent and can maintain the stoichiometric ratio of a perovskite photoactive layer 111, thereby stabilizing the perovskite photoactive layer 111. The high-performance PCBM electron transport layer 113 material of the application is dissolved by a green solvent of anisole, a commonly used food additive, thereby solving the health and environmental protection problems of using PCBM as the electron transport layer 113 material, and the combination of anisole and C60 and benzene rings in PCBM is stronger, thereby preventing PCBM from gathering in the film forming process, and making the molecules orderly stacked, and preparing a more uniform and dense PCBM electron transport layer 113 film. Meanwhile, the high-performance PCBM is doped with a certain proportion of lithium salt and organic polymer material, the conductivity of PCBM is significantly improved after doping the lithium salt, the electron mobility is improved, the film forming quality of PCBM is improved after doping the organic polymer material, the surface roughness of the PCBM film is reduced, and the carrier recombination center is reduced, thereby improving the conductivity of the electron transport layer 113 prepared by doping PCBM with lithium salt and organic polymer material, improving the electron mobility, reducing the series resistance, increasing the carrier recombination resistance, reducing the carrier recombination, thereby improving the electron transport and extraction efficiency, and further improving the open-circuit voltage (Voc), short-circuit current (Jsc) and fill factor (FF) of the prepared perovskite solar cell 100, and finally improving the efficiency of the perovskite solar cell 100 and module. In addition, the high-performance PCBM electron transport layer 113 material of the application is also doped with a certain proportion of methylamine halide salt, thereby making up the Pb vacancy defects of the perovskite photoactive layer 111 due to the escape of methylamine ions in the annealing process, maintaining the stoichiometric ratio of the perovskite photoactive layer 111, stabilizing the perovskite photoactive layer 111 and improving the stability of the perovskite solar cell 100 and module. Using the high-performance PCBM as the electron transport layer 113 material of the application not only solves the environmental protection and health problems of using PCBM to prepare the electron transport layer 113 in the prior art, but also improves the photovoltaic performance of the perovskite solar cell 100 and module prepared by using PCBM, stabilizes the perovskite photoactive layer 111 and improves the stability of the perovskite solar cell 100 and module. The perovskite solar cell 100 and module prepared by using the application have good photovoltaic performance, simple preparation process, short process time, low cost, environmental protection and health, good stability, and are suitable for the industrialization of perovskite solar cells 100, and are conducive to promoting the commercial application of perovskite solar modules.

[0070] The technical solutions of the application are further described in detail below by means of several embodiments and in conjunction with the drawings. However, the selected embodiments are only used to illustrate the application, and do not limit the scope of the application.

[0071] Embodiment 1

[0072] The embodiment provides a manufacturing process example of a perovskite solar cell 100, and the manufacturing process is specifically shown as follows.

[0073] An FTO transparent electrode is evaporated on a clean transparent substrate glass, and then 40nm of NiOx is vacuum sputtered on the FTO transparent electrode by plasma deposition (RPD) to obtain a hole transport layer 112.

[0074] A 1.2M perovskite solution is spin-coated on the NiO x , and is annealed at 130 DEG C for 15min to form a perovskite light-sensitive layer 111.

[0075] A PCBM anisole solution doped with 6wt% of lithium bistrifluoromethylsulfonylimide, 6wt% of PMMA and 3wt% of MAI (the concentration of PCBM is 20mg / mL) is spin-coated on the perovskite light-sensitive layer 111 at a rotation speed of 3000r / s, and is annealed at 100 DEG C for 10min to form a high-performance PCBM electron transport layer 113.

[0076] Finally, a transparent electrode IWO is vacuum deposited on the electron transport layer 113 to obtain the perovskite solar cell 100, marked as A1.

[0077] Embodiment 2

[0078] The embodiment shows a manufacturing process of a perovskite solar cell 100, which is basically the same as the manufacturing method in the embodiment 1, and the difference is that:

[0079] A PCBM anisole solution doped with 6wt% of lithium bistrifluoromethylsulfonylimide, 10wt% of PMMA and 5wt% of MAI (the concentration of PCBM is 15mg / mL) is spin-coated on the perovskite light-sensitive layer 111 at a rotation speed of 3000r / s, and is annealed at 80 DEG C for 15min to form a high-performance PCBM electron transport layer 113; finally, the perovskite solar cell A2 is prepared.

[0080] Embodiment 3

[0081] The embodiment shows a manufacturing process of a perovskite solar cell 100, which is basically the same as the manufacturing method in the embodiment 1, and the difference is that:

[0082] A PCBM anisole solution doped with 10wt% of lithium bistrifluoromethylsulfonylimide, 2wt% of PMMA and 1wt% of MAI (the concentration of PCBM is 30mg / mL) is spin-coated on the perovskite light-sensitive layer 111 at a rotation speed of 3000r / s, and is annealed at 120 DEG C for 5min to form a high-performance PCBM electron transport layer 113; finally, the perovskite solar cell A3 is prepared.

[0083] Comparative Example 1

[0084] The comparative example illustrates a preparation process of a perovskite solar cell 100, which is basically consistent with the preparation method in Example 1, except that:

[0085] The organic polymer and the methylamine halide salt are omitted, and a PCBM anisole solution doped with 6wt% of lithium bistrifluoromethylsulfonylimide and 6wt% of PMMA (the concentration of PCBM is 20mg / mL) is spin-coated on the perovskite light-sensitive layer 111 at a rotation speed of 3000r / s, and then annealed at 100°C for 10min to form the electron transport layer 113; finally, the perovskite solar cell B2 is prepared.

[0086] Comparative Example 2

[0087] The comparative example illustrates a preparation process of a perovskite solar cell 100, which is basically consistent with the preparation method in Example 1, except that:

[0088] The methylamine halide salt is omitted, and a PCBM anisole solution doped with 6wt% of lithium bistrifluoromethylsulfonylimide and 6wt% of PMMA (the concentration of PCBM is 20mg / mL) is spin-coated on the perovskite light-sensitive layer 111 at a rotation speed of 3000r / s, and then annealed at 100°C for 10min to form the electron transport layer 113; finally, the perovskite solar cell B2 is prepared.

[0089] Comparative Example 3

[0090] The comparative example illustrates a preparation process of a perovskite solar cell 100, which is basically consistent with the preparation method in Example 1, except that:

[0091] The organic polymer is omitted, and a PCBM anisole solution doped with 6wt% of lithium bistrifluoromethylsulfonylimide and 3wt% of MAI (the concentration of PCBM is 20mg / mL) is spin-coated on the perovskite light-sensitive layer 111 at a rotation speed of 3000r / s, and then annealed at 100°C for 10min to form the electron transport layer 113; finally, the perovskite solar cell B3 is prepared.

[0092] Comparative Example 4

[0093] The comparative example illustrates a preparation process of a perovskite solar cell 100, which is basically consistent with the preparation method in Example 1, except that:

[0094] The lithium salt and the methylamine halide salt are omitted, and a PCBM anisole solution doped with 6%wt of PMMA and 3wt% of MAI (the concentration of PCBM is 20 mg / mL) is spin-coated on the perovskite photoactive layer 111 at a rotation speed of 3000 r / s, and then annealed at 100°C for 10 min to form the electron transport layer 113; finally, the perovskite solar cell B5 is prepared.

[0095] Comparative Example 5

[0096] The comparative example illustrates a preparation process of a perovskite solar cell 100, which is basically consistent with the preparation method in Example 1, except that:

[0097] The lithium salt and the methylamine halide salt are omitted, and a PCBM anisole solution doped with 6%wt of PMMA and 3wt% of MAI (the concentration of PCBM is 20 mg / mL) is spin-coated on the perovskite photoactive layer 111 at a rotation speed of 3000 r / s, and then annealed at 100°C for 10 min to form the electron transport layer 113; finally, the perovskite solar cell B5 is prepared.

[0098] Comparative Example 6

[0099] The comparative example illustrates a preparation process of a perovskite solar cell 100, which is basically consistent with the preparation method in Example 1, except that:

[0100] The lithium salt and the methylamine halide salt are omitted, and a PCBM anisole solution doped with 6%wt of PMMA and 3wt% of MAI (the concentration of PCBM is 20 mg / mL) is spin-coated on the perovskite photoactive layer 111 at a rotation speed of 3000 r / s, and then annealed at 100°C for 10 min to form the electron transport layer 113; finally, the perovskite solar cell B5 is prepared.

[0101] Comparative Example 7

[0102] The comparative example illustrates a preparation process of a perovskite solar cell 100, which is basically consistent with the preparation method in Example 1, except that:

[0103] The lithium salt and the methylamine halide salt are omitted, and a PCBM anisole solution doped with 6%wt of PMMA and 3wt% of MAI (the concentration of PCBM is 20 mg / mL) is spin-coated on the perovskite photoactive layer 111 at a rotation speed of 3000 r / s, and then annealed at 100°C for 10 min to form the electron transport layer 113; finally, the perovskite solar cell B5 is prepared.

[0104] Comparative Example 8

[0105] The comparative example illustrates a preparation process of a perovskite solar cell 100, which is basically consistent with the preparation method in Example 1, except that:

[0106] The lithium salt, organic polymer and methylamine halide salt are omitted, and the solvent is replaced. A chlorobenzene solution of PCBM (the concentration of PCBM is 20 mg / mL) is spin-coated on the perovskite light-sensitive layer 111 at a rotation speed of 3000 r / s, and annealed at 100°C for 10 min to form an electron transport layer 113. Finally, a perovskite solar cell B8 is prepared.

[0107] Performance test

[0108] The perovskite solar cells 100A1-A3 and B1-B8 obtained in Examples 1-3 and Comparative Examples 1-8, respectively, are tested by using a simulated light source system, and the related performance test results are shown in Table 1.

[0109] Table 1: Photovoltaic performance test results of the perovskite solar cells A1-A3 and B1-B8 obtained in each example and comparative example

[0110]

[0111] As can be seen from Table 1, the open-circuit voltage, short-circuit current and fill factor of the perovskite solar cell 100A1-A3 prepared by using the PCBM phenyl methyl ether solution doped with lithium salt, organic polymer material and methylamine halide to prepare the electron transport layer 113 are obviously improved compared with the perovskite solar cell 100B7 and B8 prepared by using the PCBM solution without doping lithium salt, organic polymer material and methylamine halide to prepare the electron transport layer 113, thereby obviously improving the efficiency of the device. This is mainly due to the fact that after doping lithium salt, organic polymer material and methylamine halide in PCBM, the conductivity of the prepared electron transport layer 113 is improved, the defects generated by the escape of methylamine ions during the annealing and heating process of the perovskite light-sensitive layer 111 are supplemented, the stoichiometric ratio of the perovskite light-sensitive layer 111 is maintained, the Pb vacancy defect center is reduced, and the prepared electron transport layer 113 has good film quality and is more dense and uniform, thereby reducing the carrier recombination center, improving the electrical properties of PCBM and the stability of the perovskite light-sensitive layer 111, and further improving the open-circuit voltage (Voc), short-circuit current (Jsc), fill factor (FF) and efficiency (PCE) of the prepared perovskite solar cell and module, and the stability of the perovskite solar cell 100 and module; in addition, the open-circuit voltage (Voc), short-circuit current (Jsc) and fill factor (FF) of the perovskite solar cell 100A1-A3 prepared by using the PCBM phenyl methyl ether solution doped with lithium salt, methylamine halide and organic polymer material to prepare the electron transport layer 113 are also improved compared with the perovskite solar cell 100B1-B6 prepared by using the PCBM phenyl methyl ether solution doped with only one or two of lithium salt, organic polymer material or methylamine halide to prepare the electron transport layer 113. This is mainly due to the fact that doping lithium salt, organic polymer material and methylamine halide in PCBM has a certain synergistic effect, thereby improving the open-circuit voltage (Voc), short-circuit current (Jsc), fill factor (FF) and efficiency (PCE) of the prepared perovskite solar cell 100 and module.

[0112] As can be seen from Table 1, the open-circuit voltage (Voc), short-circuit current (Jsc), fill factor (FF) and efficiency (PCE) of the perovskite solar cell 100B7 prepared by using the PCBM phenyl methyl ether solution to prepare the electron transport layer 113 are slightly improved compared with the perovskite solar cell 100B8 prepared by using the PCBM chlorobenzene solution to prepare the electron transport layer 113 in the prior art, which is mainly due to the fact that the combination ability of phenyl methyl ether with the benzene ring and C60 in PCBM is stronger than that of chlorobenzene, thereby preventing PCBM from aggregating during the film forming process, making the molecular arrangement more ordered, reducing defects, and preparing a more uniform and dense film, thereby reducing the carrier recombination center and further improving the photovoltaic performance of the corresponding perovskite solar cell 100.

[0113] It should be understood that the above-described embodiments are merely exemplary of the technique concept and characteristics of the present application, and are intended to give a person skilled in the art a comprehensive understanding of the present application and to enable him to implement the present application, and cannot limit the protection scope of the present application. Any equivalent changes or modifications made according to the spirit and principle of the present application shall be covered within the protection scope of the present application.

Claims

1. A coating solution for preparing a PCBM electron transport layer, comprising a PCBM precursor and a solvent, characterized in that, It also includes lithium salts, organic polymers, and methylamine halide salts. The organic polymers include any one or a combination of two or more of PMMA, PEI, and PEG. The solvent includes anisole. The lithium salts, organic polymers, methylamine halide salts, and anisole work synergistically to improve the performance of perovskite solar cells and modules prepared based on the PCBM electron transport layer.

2. The coating liquid according to claim 1, characterized in that, The lithium salt includes any one or a combination of two or more of lithium bis(trifluoromethyl)sulfonylimide, lithium bis(fluorosulfonyl)imide, and lithium trifluoromethanesulfonate.

3. The coating liquid according to claim 1, characterized in that, In the coating solution, the mass of the lithium salt is 2-10% of the mass of the PCBM precursor.

4. The coating liquid according to claim 1, characterized in that, In the coating liquid, the mass of the organic polymer is 2-10% of the mass of the PCBM precursor.

5. The coating liquid according to claim 1, characterized in that, The methylamine halide salt includes any one or a combination of two or more of MACl, MABr, and MAI.

6. The coating liquid according to claim 1, characterized in that, In the coating solution, the mass of the methylamine halide salt is 1-5% of the mass of the PCBM precursor.

7. The coating liquid according to any one of claims 1-6, characterized in that, The concentration of the PCBM precursor in the coating solution is 15-30 mg / mL.

8. A method for fabricating a PCBM electron transport layer, characterized in that, include: Provide a coating solution for preparing a PCBM electron transport layer as described in any one of claims 1-7; The coating liquid is used to coat and form a liquid film; The liquid film is subjected to heat treatment to obtain the PCBM electron transport layer.

9. The preparation method according to claim 8, characterized in that, The heat treatment is performed at a temperature of 80-120℃ for 5-15 minutes.

10. A perovskite device, comprising a hole transport layer, a perovskite photosensitive layer, and an electron transport layer, characterized in that, The electron transport layer is prepared by the preparation method according to any one of claims 8-9; The perovskite device further includes a conductive substrate and an electrode layer, wherein the conductive substrate, hole transport layer, perovskite photosensitive layer, electron transport layer and electrode layer are stacked sequentially along a predetermined direction.

11. The perovskite device according to claim 10, characterized in that, The conductive substrate includes a carrier glass and a transparent conductive film coated on the surface of the carrier glass.

12. The perovskite device according to claim 10, characterized in that, The thickness of the hole transport layer is 20-100 nm; And / or, the thickness of the perovskite photosensitive layer is 400nm-700nm; And / or, the thickness of the electron transport layer is 40-120 nm.

13. A method for fabricating a perovskite device, characterized in that, include: The step of forming a hole transport layer on the surface of a conductive substrate; The step of forming a perovskite photosensitive layer on the surface of the hole transport layer; The step of forming an electron transport layer on the surface of the perovskite photosensitive layer using the preparation method according to any one of claims 8-9; as well as The step of forming an electrode layer on the surface of the electron transport layer.

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